Preparation and characterisation of heterobimetallic copper-tungsten hydride complexes

Tweaking the bridge in metallocene Zr(IV)/W(IV) bimetallic hydrides

Zirconocene cations react with Cp₂WH₂ affording the bimetallic [Cp₂Zr(μ-H)(μ-η¹:η⁵-C₅H₄)WHCp]⁺ bridging hydride 1 (Cp = cyclopentadienyl anion, C₅H₅^-) via σ-bond metathesis. Complex 1 features an atypical out of plane Zr(μ-H)W moiety, where no intermetallic interaction is involved, and a fluxional core. Coordination geometry and bond distances of the bridging hydride interaction can be modulated upon reaction with Lewis bases and unsaturated substrates. PMe₃, P(p-tol)₃, 3,5-dimethylpyridine and THF bind to 1 and shift the hydride bridge on the coordination plane of Zr. Insertion of olefins and alkynes into the Zr-C bond of 1 leads instead to alkyl and vinyl species where the Zr and W coordination planes are perpendicular to each other. Such alterations of the Zr(μ-H)W arrangement are reflected in the average ¹H NMR chemical shift values of the hydride, which correlate linearly with computed Zr-H distances. Reactivity experiments with H₂ showed that the bridging hydride interaction prevents bimetallic cooperativity and that σ-bond metathesis between Zr-C and H-H bonds is the preferred pathway for all the investigated complexes.

Zintl cluster supported low coordinate Rh(i) centers for catalytic H/D exchange between H2 and D2

We describe the synthesis of the coordinatively unsaturated Zintl clusters [Rh(L){η3-Ge9(Hyp)3}] (where L = PMe3, PPh3, IMe4 or [W(Cp)2H2]). These species are active catalysts in H/D exchange and C–H bond activation reactions.

Reactivities of Interstitial Hydrides in a Cu11 Template: En Route to Bimetallic Clusters

In sharp contrast to surface hydrides, reactivities of interstitial hydrides are difficult to explore. When treated with a metal ion (Cu⁺ , Ag⁺ , and Au⁺ ), the stable Cu^I dihydride template [Cu₁₁ H₂ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ ] (H₂ Cu₁₁ ) generates surprisingly three very different compounds, namely [CuH₂ Cu₁₁ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ ]⁺ (1), [AgH₂ Cu₁₄ {S₂ P(Oⁱ Pr)₂ }₆ ((C≡CPh)₆ ]⁺ (2), and [AuCu₁₁ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ Cl] (3). Compounds 1 and 2 are both M^I species and maintain the same number of hydride ligands as their H₂ Cu₁₁ precursor. Neutron diffraction revealed the first time a trigonal-pyramidal hydride coordination mode in the AgCu₃ environment of 2. 3 has no hydride and exhibits a mixed-valent [AuCu₁₁ ]¹⁰⁺ metal core, making it a two-electron superatom.

Facile synthesis of air-stable heterobimetallic osmium-silver hydride complexes

The synthesis and characterization of air-stable heterobimetallic Os-Ag hydrides are described. All of the new heterobimetallic Os-Ag hydrides are neutral, and the in situ generated and presynthesized cis-[Os](H)-CC-R units in these frameworks act as organometallic bidentate chelating ligands coordinating with the AgPPh₃ cation, which makes these complexes more stable. Our results provide a new synthetic route for the construction of stable heterobimetallic complexes.